Computer aided design (CAD) software tools are often used to prepare a CAD model or models representing a structure, such as a building. A CAD model can include a physical model, i.e., representations of physical elements, such as columns, beams, and the like that will be included in the structure. Drawings prepared from such a CAD model can be used in the actual physical construction of the corresponding structure. The CAD model may be prepared and edited by various individuals, including architects and structural engineers. As part of a design stage, a structural analysis is typically performed on components that will be included in the structure, for example, to ensure that there is sufficient load bearing capacity.
Structural analysis software is available to facilitate an analysis phase of a project. Conventional structural analysis software receives as input an analytical representation of a structure. An analytical representation of a structure is different than a representation of the physical elements, e.g., columns, beams, etc. It is an idealized mathematical model that may represent only a portion of a building such as one floor of a building. For example, an analytical representation may be a wire frame representation of the physical elements, and the wire frame elements can include or be associated with properties (e.g., weight, moment of inertia, cross-sectional area), member connectivity and/or end conditions (e.g., pinned, free, fixed). Typically, the analytical representation is prepared separately and is used for the structural analysis and perhaps other types of analyses that are performed in the design stage.
The analytical representation can be subjected to load simulation in a structural analysis program, for example, to identify stress levels in the various physical elements. On the basis of the analysis, analytical elements may be modified (e.g., resized or other properties changed) and the analytical representation reanalyzed in an iterative fashion. The results of the analysis can be used to update corresponding physical elements in the CAD model.
Analytical representations can be automatically generated from a CAD model. Users commonly simplify such analytical representations to reduce the amount of analytical noise generated in the analysis results. Sometimes users also manipulate the analytical representation to capture eccentricities such as a torque or turning not manifest in the physical model. These and other changes to an analytical representation can lead to errors in the analysis, however. For example, an analytical element in the analytical representation can be accidentally moved too far from a corresponding physical element in the CAD model. Other errors may be related to the CAD model itself. If a physical element's end conditions are not supported correctly, for instance, the analysis may be indeterminate and mathematically unsolvable.
For users to find out that an analytical representation is invalid they commonly are required to export an analytical representation of a CAD model to a structural analysis program. The nature of typical structural analysis methods is such that once an error has been discovered, the analysis terminates without producing meaningful results. Users must go back and remedy the problem in the analytical representation, export the analytical representation, and perform the analysis again. Sometimes an analysis may run for a long time before another error in the analytical representation is discovered. This frustrating, time consuming process can be repeated many times.